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ICD-10-CM 2027 diagnosis code

K21.0Gastro-esophageal reflux disease with esophagitis

Not billable — use a more specific code

K21.0 is a header code, so it can't be reported by itself. Choose one of the 2 more specific codes beneath it.

Code last changed in FY2021 (effective October 1, 2020). Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About K21.0

K21.0 is the ICD-10-CM diagnosis code for Gastro-esophageal reflux disease with esophagitis. It belongs to category K21 (Gastro-esophageal reflux disease), block K20-K31 (diseases of esophagus, stomach and duodenum) and chapter 11 (diseases of the digestive system). It is a header code, so it can't be reported by itself; one of its 2 subcodes must be used instead.

Within K21 (Gastro-esophageal reflux disease), K21.0 is specifically for Gastro-esophageal reflux disease with esophagitis. Related codes cover without esophagitis (K21.9).

To report this condition, pick the subcode that matches the documentation: K21.00 (without bleeding) and K21.01 (with bleeding).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015, and changed in FY2021 (expanded into subcodes).

Before ICD-10, this condition was coded in ICD-9-CM as 530.11 (reflux esophagitis).

Specific codes under K21.0

Notes that apply from higher levels

Instructions written at a parent level also apply to K21.0.

› From K21 Gastro-esophageal reflux disease
Excludes1
  • newborn esophageal reflux (P78.83)

Broader instructions also apply from K20-K31 Diseases of esophagus, stomach and duodenum and Chapter 11: Diseases of the digestive system.

Codes whose notes reference K21.0

ICD-9-CM equivalent

Converter →

From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • FY2021 (effective 10/1/2020): Expanded — no longer billable

Common questions about K21.0

Is K21.0 billable?

No. K21.0 is a header code. Report one of its more specific subcodes instead.

What is the ICD-9 code for K21.0?

The CMS General Equivalence Mappings map K21.0 to ICD-9-CM 530.11.